Locking means for an insert

ABSTRACT

Locking bracket for a slider in a dovetail slot ( 3 ), where a further dovetail slot ( 4 ) is arranged perpendicularly to the first dovetail slot ( 3 ), in which a locking bracket ( 5 ) can be displaced from a position whereby the glider is locked by the locking bracket ( 5 ) to a position where the glider is free to be moved passed the locking bracket ( 5 ) and that a screw ( 6 ) captures the locking bracket ( 5 ) through a countersunk hole in the locking bracket ( 5 ), whereby the locking bracket is maintained or released by loosening the screw ( 6 ).

[0001] The present invention is related to a locking means for aninsert, especially for clamping jaws for clamping drill pipes andcasings during drilling operations.

[0002] Inserts which are guided into a tool dovetail slot, as insertsare used in clamping jaws in the petroleum industry, traditionally arelocked with loose screws at both ends. To replace such inserts thescrews have to be removed, which is connected with the risk of loosingscrews down into the drilling hole. Furthermore the operation is timeconsuming.

[0003] With the locking means according to the present invention theabove mentioned disadvantages with known solutions, are avoided. This isachieved with the locking means according to the present invention asdefined with the features stated in the claims.

[0004] The drawing discloses a section of a locking jaw in a perspectiveview where some of the inserts are locked.

[0005] The FIGURE discloses a section of a clamping jaw, the internallower portion of which is cut conically downwardly and outwardly toavoid damage on the section during operations.

[0006] The inserts 2 may be guided into dovetail slot 3. The slots havethe same length as the inserts 2 such that the inserts may be guided toabutment and the end of the slot.

[0007] Perpendicularly to the slots 3 a second dovetail slot 4 isarranged, in which a locking bracket 5 can be displaced to overlap theend of the insert 2 or in the opposite direction to release the insert 2so this can be pulled out.

[0008] The locking bracket 5 comprises a keyhole shaped hole throughwhich a screw 6 is secured to the section 1 of the clamping jaw. Thelarger opening of the hole is countersunk in such a way that the screw 6may be screwed completely down into the locking bracket 5.

[0009] For replacement of the insert 2 the screw 6 is released so muchthat the locking bracket 5 can be displaced away from the end of theinsert 2, where after the insert 2 easily can be displaced out of thedovetail slot 3 and a new insert may be inserted. The locking bracket 5suitably can be provided with a spring ensuring that the locking bracket5 is displaced away from the insert 2 when the screw is released. Thescrew 6 slides in the keyhole slot and thereby is captured in thedovetail slot 4.

[0010] Thereafter the insert 2 is locked by displacing the end of thelocking bracket 5 above the end of the insert 2 where after the bracket2 is fixed by the screw 6. This movement may be achieved by tighteningthe screw 6 into the countersink whereby the locking bracket 5 isdisplaced in correct position to lock the insert against movement.

[0011] The clamping jaws preferably are made of special steel with goodabrasion resistant properties, giving the dovetail slots 3 and 4 a longlifetime.

[0012] Without further elaboration, it is believed that one skilled inthe art can, using the preceding description, utilize the presentinvention to its fullest extent. The following preferred specificembodiments are, therefore, to be construed as merely illustrative, andnot limitative of the remainder of the disclosure in any way whatsoever.

[0013] In the foregoing and in the following examples, all temperaturesare set forth uncorrected in degrees Celsius and, all parts andpercentages are by weight, unless otherwise indicated.

[0014] The entire disclosure of all applications, patents andpublications, cited herein and of corresponding Norway application No.2001 5551, filed Nov. 13, 2001 is incorporated by reference herein.

[0015] The preceding examples can be repeated with similar success bysubstituting the generically or specifically described reactants and/oroperating conditions of this invention for those used in the precedingexamples.

[0016] From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention and, withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

1. Locking bracket for a slider in a dovetail slot (3), characterized inthat a further dovetail slot (4) is arranged perpendicularly to thefirst dovetail slot (3), in which a locking bracket (5) can be displacedfrom a position whereby the glider is locked by the locking bracket (5)to a position where the glider is free to be moved passed the lockingbracket (5) and that a screw (6) captures the locking bracket (5)through a countersunk hole in the locking bracket (5), whereby thelocking bracket is maintained or released by loosening the screw (6). 2.Locking bracket according to previous claim, characterized in the screw(6) having an internal hexagon, preferably the screw is a socket setscrew.
 3. Locking bracket according to previous claims, characterized inthe conical countersink in the locking bracket (5) may be used todisplace the locking bracket from a free to a locket position bytightening the screw (6).